source: http://www.securityfocus.com/bid/13979/info
osCommerce is prone to multiple HTTP response splitting vulnerabilities. These issues are due to a failure in the application to properly sanitize user-supplied input.
A remote attacker may exploit any of these vulnerabilities to influence or misrepresent how Web content is served, cached or interpreted. This could aid in various attacks that attempt to entice client users into a false sense of trust.
http://www.example.com/index.php?action=buy_now&products_id=22%0d%0atest:%20poison%20headers!
http://www.example.com/index.php?action=cust_order&pid=2%0d%0atest:%20poison%20headers!